1. Field of the Invention
The present invention relates to a resist pattern thickening material capable of forming a fine space pattern of resist, exceeding exposure limits (resolution limits) of light sources of available exposure devices by thickening a resist pattern to be formed when manufacturing a semiconductor device, and the present invention also relates to a method for forming a resist pattern, a semiconductor device, and a method for manufacturing the semiconductor device.
2. Description of the Related Art
Semiconductor integrated circuits are becoming more highly integrated, and LSIs and VLSIs are increasingly being put into practical use. Accompanying this trend, interconnection patterns are more finely formed. To form a fine interconnection pattern, a lithographic technique is very useful in which a substrate is coated with a resist film, is selectively exposed, and thereafter, is developed to thereby form a resist pattern, and the substrate is subjected to a dry etching treatment by using the resist pattern as a mask, and thereafter, by removing the resist pattern, the desired pattern, for example, an interconnection pattern is obtained. Utilization of such a lithographic technique with the use of an exposure light for microfabrication is still strongly demanded to keep high-productivity of patterns even now patterns are becoming increasingly fine. For this reason, for a light used for exposure, i.e, an exposure light, not only a deep ultraviolet light having a shorter wavelength has been pursued, but also various inventive efforts have been done for mask pattern itself, for the shape of light source and the like. There is still much demand for developments of a technique allowing for life-prolonging of an exposure light to draw a fine pattern in an easy method.
To overcome the above technical problems, there has been proposed a technique that a resist pattern formed from a conventional resist material is thickened with the use of a resist pattern thickening material (hereinafter, may be sometimes referred to as “resist swelling material”) capable of forming a fine space pattern of resist to thereby form a fine pattern. For example, a technique has been proposed in which a resist pattern is formed, then an aqueous solution material containing a polyvinyl acetal resin and a silicone resin each capable of affording crosslinkability as a base is applied over a surface of the resist pattern to form a coated film, the coated film is heated to thereby subjecting the coated film and the resist pattern to a crosslinking reaction at the contact interface therebetween by utilizing a residual acid in the resist pattern, and then the resist pattern is thickened (hereinafter, may be sometimes referred to as “swelled”) by rinsing the surface of the crosslinked resist pattern with water or an alkaline aqueous solution to thereby shorten a distance between the respective lines of the resist pattern and form a fine space pattern of resist, thereby forming a desired pattern, for example, a desired interconnection pattern formed in the same shape as in the space pattern of resist (see Japanese Patent Application Laid-Open (JP-A) No. 11-283910). Further, for the above-noted aqueous solution material, a composition with a crosslinker further added thereto is proposed in view that a substantial amount of reduction of the width of space pattern of resist can be expected.
However, the type of chemical agents that can be linked to a coater/developer track to be used in semiconductor process at present is limited to resist materials and rinse solutions, and it is very difficult to set up a new process line for a new chemical agent. In the conventional semiconductor process, it is not based on the assumption that an aqueous solution material is applied over a surface of a resist pattern, and thus it is also difficult to use such an aqueous solution material because of the necessity of a new control for waste fluid.
In addition, with the use of such a conventional material composition utilizing a crosslinking reaction, it is difficult to control the amount of reaction, and there are the following shortcomings. It is liable to cause differences in the amount of reaction depending on the initial pattern size of a resist pattern, loss of a resist pattern caused by an embedded space pattern of resist, dependence of the amount of reaction on the used pattern shape and the like, and the process margin is narrow.
From the perspective of forming a fine interconnection pattern, it is desired to utilize, as an exposure light, for example, an ArF (argon fluoride) excimer laser light having a wavelength of 193 nm which has a shorter wavelength than that of a KrF (krypton fluoride) excimer laser light (wavelength: 248 nm). In the meanwhile, when a pattern is formed utilizing an X-ray, an electron beam, or the like, each of which has a further shorter wavelength than that of the ArF (argon fluoride) excimer laser light (wavelength: 193 nm), it results in a high-cost and a low-productivity. Therefore, it is desirable to utilize the ArF (argon fluoride) excimer laser light (wavelength: 193 nm).
With the use of the composition for the aqueous solution material described in Japanese patent Application Laid Open (JP-A) No. 11-283910, it has been known that the use of the aqueous solution material composition is not effective in thickening (swelling) an ArF resist pattern containing a resin which is different from the resin used for KrF resist patterns, although it is effective in thickening (swelling) a KrF resist pattern using a phenol resin, and there is a problem that the aqueous solution material composition cannot be utilized for ArF resists which are typically used for processing advanced devices.
Furthermore, a reduced resist pattern using the polyvinyl acetal resin as a base, which is obtained by the technique described in Japanese Patent Application Laid-Open (JP-A) No. 11-283910 may be sometimes insufficient in dry etch resistance to cause a problem with processability. In the meanwhile, in case of a resist pattern using the silicone resin as a base, an etching residue of the silicone resin occurs, and therefore, it is often needed to further remove the residue, and the resist pattern is not practical, although the dry etch resistance thereof is satisfactorily provided.
Therefore, it is desired to develop a technique for forming a fine space pattern of resist and forming an interconnection pattern, etc. which is capable of using ArF (argon fluoride) excimer laser light as a light source during patterning without the necessity of setting up a new device, which is capable of sufficiently thickening an ArF resist pattern, etc. that cannot be sufficiently thickened or swelled by using the aqueous solution material containing the crosslinkable resin or the resin containing a crosslinker, at low cost, easily.
The present invention aims at solving the shortcomings in the prior art, and can achieve the following objects.
An object of the present invention is to provide a resist pattern thickening material which can utilize also an ArF (argon fluoride) excimer laser light as an exposure light during patterning; which is capable of thickening a resist pattern such as a lines & spaces pattern without depending on the size of a resist pattern to be thickened by only applying the resist pattern thickening material over the surface of the formed resist pattern formed from the ArF resist or the like; which can be rinsed with water or an alkaline developer; which is excellent in etch resistance; and which is capable of forming a fine space pattern of resist, exceeding exposure limits (resolution limits) of light sources of available exposure devices, at low cost, easily, and efficiently.
Another object of the present invention is to provide a method for forming a resist pattern which, during patterning a resist pattern, can utilize also an ArF excimer laser light as an exposure light without the necessity of setting up a new device; which is capable of thickening a resist pattern such as a lines & spaces pattern without depending on the size of a resist pattern to be thickened; and which is capable of forming a fine space pattern of resist, exceeding exposure limits (resolution limits) of light sources of available exposure devices, at low cost, easily, and efficiently.
Yet another object of the present invention is to provide a method for manufacturing a semiconductor device in which, during patterning a resist pattern, ArF excimer laser light can be utilized as a light source without the necessity of setting up a new device; a fine space pattern of resist, exceeding exposure or resolution limits of light sources of available exposure devices, can be formed; and which can efficiently mass-produce a high performance semiconductor having a fine interconnection pattern formed using the space patter of resist, and is to also provide a high performance semiconductor which is manufactured by the method for manufacturing a semiconductor device and has fine interconnection patterns.
In view of the above-mentioned shortcomings, the inventors of the present invention have investigated vigorously, and have obtained the following findings. Specifically, the present inventors found out that in swelling of a resist pattern using a conventional resist swelling agent containing an aliphatic resin, a silicone resin, a crosslinker and the like, the resist pattern cannot be thickened without the utilization of a crosslinking reaction caused by a residual acid, however, as a substitute for the conventional method, the use of a resist pattern thickening material which contains at least a resin, a benzyl alcohol, a benzylamine, and derivatives thereof, which is a nonaqueous material and contains no acid-generator and no crosslinker makes it possible to easily control reactions as well as to thicken the resist pattern without depending on the size of a resist pattern to be thickened because no crosslinking reaction is caused therein, and the resist pattern thickening material can be rinsed with water or an alkaline developer. The present inventors also found out that it is possible to obtain a resist pattern thickening material which is excellent particularly in etch resistance when a phenol resin, polyvinylpyrolidone and the like are used as the resin. These findings led to the completion of the present invention.